code: def gradient(
      x: None,
      /,
      *,
      spacing: Union[(int, list, tuple)] = 1,
      axis: Optional[Union[(int, list, tuple)]] = None,
      edge_order: int = 1,
  ) -> Union[(None, List[None])]:
      raise IvyNotImplementedException()
  
imports: from typing import Union, Optional, Tuple, List, Sequence
  from numbers import Number
  import mxnet
  from ivy.utils.exceptions import IvyNotImplementedException
  from ivy.func_wrapper import with_supported_dtypes
  from ..None import backend_version
label_desc: Use image node_id 19 for calling a global function with example usage: gradient() without return types